If your hot water is coming out brown, yellow, or otherwise discolored, the most common causes are an aging or rusting water heater tank, sediment and mineral buildup inside the tank, or corroding galvanized pipes feeding hot water to your fixtures. Discolored hot water — whether it looks yellow, brown, or just generally dirty — is usually isolated to the hot side because the water heater tank is where rust and sediment collect; if both your hot and cold water are discolored, the issue is more likely with the main supply line itself.
To fix brown or yellow hot water, start by flushing the water heater to clear out loose sediment. If the discoloration keeps coming back or the water heater is more than 8–10 years old, the tank itself may be rusting from the inside and is a better candidate for replacement than repeated flushing. Our team at The 5 Star Plumbing can diagnose whether your dirty hot water is a sediment issue, a corroding tank, or a pipe problem, and recommend the right fix.